Looking for help building a Gas Vapor system

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[RustyLugNut]

tscombustion.com was their main gateway.

There are, fortunately, vestigial links around the web but the most readable is this discussion from AutoblogGreen.

AutoblogGreen Q&A with Transonic Combustion: Can supercritical fluids give a 30% mpg boost? - Autoblog

There is still a Wiki up and running and the source notes at the bottom are informative though some are in German ( we have a fluent German speaker on staff simply because much of the good research comes out of Germany).

https://en.wikipedia.org/wiki/Transonic_Combustion

Source 1 is the link to their 2010 SAE paper abstract. They have a 5 page review that allows you to parse more detailed information about the test engine in discussion such as it's 17.5:1 compression ratio.

Transonic Combustion - A Novel Injection-Ignition System for Improved Gasoline Engine Efficiency


They could run the engine over a range of loads without a throttle but as I understand it, there was the need to throttle the engine for emission reasons over other operating regimes. A three way catalytic converter was to be employed. When un-throttled, the engine could run at 50:1 AFR. Un-throttled operation was much like that found in diesel engines.

And here are some claims as posted in an article from an MIT Publication.

https://www.technologyreview.com/s/4...e-passes-test/

I hope this gives you some food for thought.

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[teoman]

%10 - %20 is nothing to scoff at.

If you have a fleet of vehicles, that will amount to a huge saving very quickly.

From what I understand from what has been written here, converting fuel to vapor does not change the amount of energy in the fuel. So when people say things like it takes up %1000 more volume therefore we have increased our fuel supply just sounds ignorant.

The combustion characteristics of the fuel may change when it is heated and it is in the form of vapor. This will allow you to try things such as lean burn. From my limited understanding, lean burn works well, however the leaner the mixture, the slower the combustion/burn, so you end up pushing still burning gasses out of your piston which the rest of the system is not too happy with.

So, if i were you i would be looking at how to measure lean burn in my engine before i begin this process.


Also you say that using exhaust to heat up the fuel is crap, but in my opinion that statement is not true. There may have been an implementation using exhaust heat that did not work. But exhaust heat is just heat (energy) using/harvesting and controlling the delivery of that energy is what is important. To the fuel, it does not matter where the energy came from, electrical resistance, its own burner or the exhaust is irrelevant. With our abilities it may not be practical to use exhaust heat, the temperature may not be controllable, it may not be localizable to where you want.... but heat is heat and the exhaust is a free source of it.

A heatpipe could deliver the energy from the exhaust to a very localized area, have a look at those if you want.

[Hersbird]

Originally Posted by RustyLugNut

There is some value to be had in HOT vapor combustion. Even if only a few percent is gained. The real value is in extending the combustion lean limits and producing torque in lean burn mode far beyond what is common. PgfPro's Unique Talon is proof of that. People have asked why the Smokey Engine hasn't been reproduced, well, in essence it has and PgfPro has only scratched the surface.

Right, so lets start a thread on lean burn, that is where the most potential benefits are to be had here, not with vapor carbs. You can do it with custom tuning on standard FI systems. I would bet though just like with manufactures having to ditch lean burn, it doesn't meet modern ultra low emissions requirements. I have long wondered what kind of economy we are giving up at the expense of ultra clean emissions.

[RustyLugNut]

Originally Posted by Hersbird

Right, so lets start a thread on lean burn, that is where the most potential benefits are to be had here, not with vapor carbs. You can do it with custom tuning on standard FI systems. I would bet though just like with manufactures having to ditch lean burn, it doesn't meet modern ultra low emissions requirements. I have long wondered what kind of economy we are giving up at the expense of ultra clean emissions.

The problem, as you pointed out, is emissions. However, it is not as one would think. NOx drops drastically after about 18:1 mass AFR as the combustion temperatures fall. The problem becomes the erratic nature of lean combustion. When the coefficient of variability (COV) of the pressure trace exceeds 5% of scale, the combustion is defined as erratic. HC and CO spike as unburned or partially burned fuel is found in pockets of low temperature fuel mixes. Early Honda lean burn engines as well as other designs utilized EGR to add heat to the fuel mixture. They ran at 22:1 AFR. However, the slight traces of HC and CO could not be dealt with as well as what little NOx was produced since the traditional three way catalyst could not be used to deal with emissions products in a non-stoichiometric mix. However, if you could strengthen the lean combustion and all but eliminate the hydrocarbon portion of the pollutants you could then deal with the NOx as diesels currently do with NOx traps and a reducing compound.

[teoman]

Water injection may help out there. It reduces all but nox emissions.

But lean burn is slow (vapor fuel may speed it up) water injection may slow it down. Maybe water injection in the exhaust. Or urine injection.

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